Title: Characterisation and sampling of the macrobenthic community structure of coastal sublittoral soft bottom habitats in Antarctica

Description:

Abstract:

Coastal soft-bottom communities contain diverse assemblages of animals. Biological interactions and physical disturbances
are thought to be important in determining community structure on the small scale and oceanographic characteristics probably
account for much of the variation in soft bottom community structure between the east and west sides of McMurdo Sound. The
aim of this study was to describe the macro benthic communities in relation to mechanisms generating patchiness in the spatial
arrangement of macrofauna. The macro benthic community structure of coastal sub littoral soft bottom habitats was characterised
with samples collected to assess the abundance and diversity of macrofauna from soft sediment habitats at four sites in New
Harbour, 2 sites in Salmon Bay and one site at McMurdo Station. Core samples of the sediments of the sea floor were collected
by diving. The large organisms living in the sediments were extracted by sieving the sediments on a 0.5mm mesh. As many core
samples as possible were collected from as many different sites. Core samples were collected either haphazardly from the seafloor,
near but not directly under the dive hole, or were targeted on specific areas where local conditions were likely to modify
community structure. Areas sampled included patched of different sediment grain size and organic content, surface sediment
disturbance generated by large animals living on the sea floor and the presence of sponge mats. Animals collected in these
samples will be identified and differences between the east and west sides of McMurdo Sound. The contribution of local processes
to variability in density of common animals and changes in community structure will also be assessed.

Samples of macrobenthos were split between the Water Quality Centre, Hamilton and Scripps Institution of Oceanography, San
Diego. Samples will be identified and enumerated at both institutions. For more information please contact Dr Simon Thrush
at NIWA.